Improvement in autographic telegraphs



W. E. SAWYER & I. G. SMITH.

AUTOGRAPHIC TELEGRAPH.

Patented Nov.14,1876.

ATTDBNEYS:

WITNESSES WILLIAM E. SAWYER, on NEW YORK, N. Y, AND JAMES e. SMITH, or

NI'IED STATES:

HAOKENSACK, ASSIGNORS, OF ONE-HALF OF THEIR RIGHT TO ROBERT F. STOCKTON AND EDWARD J. ANDERSON, OFTRENTON, NEW JERSEY.

IMPROVEMENT IN AUTOGRAFHIC TELEGRAPHS- Specification forming part of Letters Patent No. [84,302, dated November 14, 1876; application filed September 8, 1676.

To all whom it may concern:

Be it known that we, WILLIAM EDWARD SAWYER, of the city, county, and State of New York, and JAMES GILMORE SMITH, of Hackensack,'in the county of Bergen and State of New Jersey, have invented certain new and useful Improvements in Copying or Autographic Telegraphs, of which the following is a specification:

Our invention relates to certain mechanism for accomplishing autographic or facsimile transmission of messages over linesof telegraph, and to electrical circuits connected therewith.

As the principal features of fac-simile telegraphs are well understood by those skilled in the art, we shall, as far as possible,

confine ourselves to a description of the mechanism of our present invention. I sent day the principal feature of any and all fac-simile telegraph systems is the method of obtaining accurate isochronous motion in two or more instruments distantly separated. This is what is accomplished by our present invention.

In thedrawings accompanying this specification we have not shown the motive power,

A as our improvement is of such a character that ically, each instrument being dependent upon the speed of the other for this periodical operation, as well as upon a line-current or a local current, controlled by a clock-work,

which is in some respects, perhaps, preferable'to a line-current.

With this general reference to the nature of our invention, we will proceed to describe the construction of the mechanism in detail, so

material. transmitting and recording mechanism is At the pres far as necessary to an understanding of the same by persons skilled in the art.

In the drawings accompanying and forming a part of this specification, Figure lisa plan view of our improved autographic telegraph instrument.

ing the circuit-connection of the transmitting and receiving stations. Like letters indicate similar parts in all the figures.

Referring to Fig. 1, A is thesupportingframe, which may be made of .any suitable B is the gear-wheel, by which the operated, and to which the motive power'is applied by clock-work, or'any'kind of motive power giving the steady motion. This gearwheel is placed looselyv on the shaft 0, and transfers its motion to the shaft by means of an arm, D, keyed to the shaft O, and aclutch, E, which slides on the arm D. The clutch E is connected by spiral springs F to projecting pins of arm D, and attracted or released,

- by a stationary magnet, G, the clutch being shaped at the side facing the magnet in the nature of an armature to the same. The gearwheel B is cast or otherwise provided with a small milled wheel, B, sidewise to the main" gear, the clutch being so arranged on the fixed revolving arm D as to enter the teeth of the milled section B, when not attracted; by the magnet.. Now, it is obvious that as long as the clutch E is hearing on the milled edge of the gear-wheel the shaft 0 will re-' volve but as soon as the magnet Gr draws the clutch, by means of its armature, away from the milled edge B, so as to clear the same, the motion of the shaftG willlbe ar-'" rested, while the gear will continue to revolve unobstructed, it being designed to have the natural friction of the gear revolving on the; locked shaft exactly equal to thefriction of the rest of the mechanism when the clutch: takes hold of the gear and the shaft revolves. Herein is involved the main principle of the, invention, for when, in one instrument, the

clutch-armature arrives before the magnet 95,,

Fig. 2 is a sectional side elevation of the same; and Fig. 3, a diagram showthe motion of the shaft 0 is arrested until the I clutch-armature of the distant instrument arrives at the same points, when both instruments proceed together for another revolution, as will appear from the following description of the transmitting and receiving apparatus. Upon the shaft 0, and fixed to the same, and unfixed, as desirable, (but fixed to the same, when transmitting or receiving.) is a metallic cylinder, H, insulated from the shaft, but electrically connected by a spring, K, which bears upon the cylinder. Upon and fixed to the same shaft 0 is a small gear, L, which meshesinto a larger gear, L, which is fixed to its shaft M. Bolted to the frame are two rods, ff, which are joined in a head-piece, g, in which one end of the shaft M has a bear- %Tpon the shaft M is cut a screw-thread, the object of which is to move along the rods f f the stylus-carriage N, which has a joint bearing upon the thread. Fixed to the stylus-carriage are two springs, to at, having two heads and set-screws, b b, and carrying two styles, d d.

It is obvious that, as the cylinder revolves, the style 01 is moved along its length, and, since thestyle bears upon the cylinder, a real or imaginary spiral line of any fineness is is traced upon the cylinder, or the paper or metal placed thereon, by the point of the style.

We have preferred to use, for ordinary writ ing, a thread upon the shaft M, which will.

cause the style to trace upon the cylinder a spiral one-sixtieth of an inch apart, or sixty to the inch; but, inasmuch as one writing might be so fine as to make greater minuteness desirable, we will point out that there may be two sets of gears, L L, which, while the mechanism is at rest, may be loose upon the shafts O and M, but either of which sets may be fixed to their respective shafts by a reversible clutch or changeable spring, or other device.

When it is desired to transmit a message, there is placed around the transmitting-cylinder H either a sheet of metal or metallic pa per, upon which the message is written in an insulating-ink, or the sheet upon which a message has been transferred, so as to obtain the,

same features of insulation and conductivity, the same being secured by a rubber band or bands, or in other manner; and upon the receiving-cylinder is placed a sheet of chemical paper capable of electrolyzation.

Now, as the style upon the transmitting instrument comes upon a lineof insulating writing, a mark is made by the style of the receiving'instrument upon the chemical paper, and as the styles of both instruments move along the cylinder, the entire surface is finally covered, and, as the cylinders of the two instruments move isochronously, the message is finally reproduced from the transmitting to and at the distant receiving-station.

' If two instruments could be designed which would run indefinitely at the same rate of speed, of course no regulation would be nec" essary; but it has been, and, in fact,- is, impossible to accomplish any such nicety of motion, except to a certain extent, with the slowly-vibrating pendulum, the most-accurateg It is use -ly moving of mechanical devices. essary, therefore, that the transmitting-instruments shall be regulated, either by some accurate motion independent of themselves, or some impulse common to both, so that neither shall increase its speed, except in a single revolution of the cylinders, above the other. Therefore, we have arranged that when one instrument shall arrive at a certain point upon .the cylinder, it shall wait for the other instrument to arrive at the same point, and neither instrument can pass until the other shall have arrived at that point.

Independent of the transmitting and receiving electrical circuits which we have deemed is connected to the contact-points r. as a message is being transmitted, or, rather,

so long as the cylinders are undergoing that portion of their revolution which is devoted to" transmitting and receiving, the line is con nected to the shafts C 0; but so soon as the vclutch-armatures E of the arms D arrive at the magnets G G, and are arrested there, the circuit of the line is changed from r 'I' to z z,

and thence, through ordinary relays R B, through batteries TI to the earth.

through the forward motion of the levers t t of relays R R, by separation of the contactpoints a u and o o, by which the local circuits of the magnets Gr G are closed, whereupon the cylinders of both instruments start and accomplish another revolution.

In ordinary operation one instrument will generally arrive at the arresting-point before the other; but this movement is apt to vary.

Hence it is necessary that neither should be released until the other shall have arrived at the same point, which is accomplished by our invention.

For purposes of signaling an ordinary so far as the transmitting and recording parts; are concerned, by closing the Morse keys, and" When the armatures of the relays are attracted and the-circuits of local batteries T T are broken,'

throwing open the detent-switch, it being understood that the rest of the mechanism move on uninterruptedly, if desired.

Two styles are employed, one to transmit, the other to receive, a message. Either style is brought to bear upon the cylinder H by turning round the stylus-holder N.

The clutch shown in the drawings, it is obvious, may be raised in many ways-for instance, it may be fixed intermediately upon a lever hinged upon the arm D, and carrying the armature at its free end. In this case, as

in that shown, it would be brought to a hearing upon the milled edge of the gear, by means of a spring, or the springs F F. In the drawings it is shown as sliding upon the arm D, drawn in one direction by the two springs F F, and in the other by the magnet Gr. It may equally well be drawn to the milled edge of the gear by a magnet, and thrown out in the path of a fixed projection by a spring, or to a fixed magnet by its attractive power.

It may happen that when a message shall be presented for transmission, it will not be in the right condition. In this event, it will be necessary to make an exactcopy of the same, and this is accomplished by tracing, and transferring the tracing to a metallic plate or a comlucting-surface. In order to carry out our invention in this respect we lay upon the message a transparent sheet, trace the lines of the message, and transfer the same, as above. For repeating messages,'or forwarding messages over circuits too long to be operated at a single transmission, we have resort to the same device.

It will thus be seen that in most points our invention is not essentially different from that of ordinary telegraphs, excepting in the matter of isochronous motion, where we claim to have trebled and sextuplcd the speed of transmission hitherto obtained by similar instruments.

A metallic point draws imaginary advancing lines overa' metallic surface, upon which is an insulating writing, and the interruptions of the line-circuit occasioned by the point coming upon the lines of writing effect the record at a distant station, which record,

chemical or otherwise, is a fac-simile of the insulating-lines of writing, owing to the fact that both the transmitting and receiving cylinders move isochronously, and the transmitting and recording points move isochronously.

In transmitting a message written upon a metal or a metallic surface, it is obvious that the face of the received message will be the writing penetrate, so as to be as legible inversely as obversely.

It is by no means-necessary, except in point of speed, to arrest the instruments and release them by a line-current. This may be done,

as hereinbefore indicated, by locally operatingclock pendulums at each station, and thereby a complete vibration can be made to accurately register one hundred revolutions of the cylinders per minute, and by half vibrations two hundred revolutions. They are, of

course, used simply to break the local circuits 5 of the magnets G. The variations between distant stations in temperature and latitude are regulated, as usual, by raising and lowering the pendulum weight. This is seldom necessary in the transmission of ordinary writing, but is quite necessary when maps or figures are to be sent.

Having thus described our invention, what we claim as new, and desire to secure by Letters Patent, is-

1. In a copying-telegraph, the method of obtaining isochronous motion of different instruments, consisting in throwing out of gear at a certain point and arresting the motion of the faster-running instrument until the slower-running instrument shall arrive at the same indicated point, without arresting the motion of the accompanying mechanism, substantially as herein shown and described.

2; In a copying-telegraph, transmitting or recording mechanism, operated by a clutch, which is taken off when one instrument is moving faster than another, and restored so 

